The present invention relates to a liquid sanitary cleansing and descaling agent or an agent for removing lime scale, urine scale and the like, which agent can be used particularly for cleansing toilets and other sanitary installations.
For a long time, aqueous solutions of hydrochloric acid or other mineral acids and formic acid or amidosulfonic acids have been used as descaling agents for sanitary installations and in particular toilet bowls and wash basins.
The known liquid agents contain the particular acid at a concentration of about 5% to 10%. In certain applications, mixtures of several acids, in particular hydrochloric acid with phosphoric acid, are also used. These agents contain additives such as acid-stable detergents, viscosity-increasing agents (thickeners), dyes and scents, as disclosed in German Application No. 2,359,095.
These agents are very effective in the removal of deposits of lime scale and urine scale. Bacteria and unpleasant odors, which form predominantly on the deposits of lime and urine scale, are also removed by these agents.
The most frequently used relatively strong acids, such as hydrochloric acid, phosphoric acid and formic acid, are grouped in the German water pollution class 1. Formic acid use has recently been increasing. In addition, phosphoric acid has a eutrophicating effect. Hydrochloric acid and formic acid are regarded as strong eye, respiratory tract and mucosa irritants. This characteristic accounts for the fact that liquid toilet cleansers which contain these acids can be identified even by their pungent and acrid smell.
Furthermore, it is very difficult to perfume the above-mentioned acids. The 5% to 10% acid concentrations normally used prevent the perfuming ingredient from remaining stable during prolonged storage periods. Moreover, only a few individual scents are suitable for perfuming these solutions.
German Patent Appl. No. 2,855,822 discloses cleansers for the sugar industry based on organic polycarboxylic acids which admittedly do not belong in the water pollution class 1. These cleansers are less irritating to the skin, mucosa and eyes and do not have a pungent odor. However, these cleansers perform unsatisfactorily with respect to the removal of lime scale and urine scale deposits. Attempts have therefore been made to improve the effectiveness of the polycarboxylic acids by an addition of AlCl.sub.3 and FeCl.sub.3. However, this measure is insufficient for reliable removal of the deposits in the toilet.
The liquid toilet cleansers are thickened in order to boost the action of the acids. The thickened cleansing liquid moves more slowly down vertical or inclined surfaces as a result of the higher viscosity of the solution. This provides a longer period of action of the acids so that an increase in performance is obtained, particularly in the dissolution of lime. Since strong acids and thickeners are in many cases incompatible, the possible combinations of the two groups that yield acceptable results are severely restricted.
Nonylphenol ethoxylates, which also act as surfactants, are frequently used for thickening the acid solutions. These surfactants, which are regarded as difficult to degrade biologically, must in general be employed in high concentrations of between about 6% to 10% in order to be effective. It is therefore desirable to replace nonylphenol ethoxylates by other, less polluting thickeners.
Typical pure thickeners, such as guar flour or xanthan gum are not sufficiently stable in these acid media during storage and can therefore not be used. At moderate temperatures of about 36.degree. C., products using these pure thickeners become highly mobile in less than one week.
German Application No. 2,359,095, mentioned above, discloses the thickening with alkoxylated amines of mineral acid based cleansers. Relatively expensive solubilizers must be added to solutions that are thickened with alkoxylated amines in order to avoid phase separation of perfume oils during short storage periods. Frequently, larger quantities of thickener are then used in order to obtain the desired viscosity.